Binary nematic mixtures of 4,4'-dialkoxyazoxybenzene homologs

UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
Mary Anna Andrews (Creator)
The University of North Carolina at Greensboro (UNCG )
Web Site:
J. Schroeder

Abstract: Four phase diagrams of binary mixtures of nematogenic dialkoxyazoxybenzenes were constructed by determining the melting range and nematic-isotropic (N-I) transition range of various compositions of the binary systems. The components included 4,4'-dimethoxy- (la), 4,4'-diethoxy- (lb), 4,4'-di-n- butyloxy- (lc) and 4,4'-di-n-hexyloxyazoxybenzene (ld). All mixtures give nematic mesophases in which the molecular order is intermediate relative to the nematic mesophase of the pure components. The eutectic mixtures generally exhibit the widest nematic range. The noneutectic mixtures having N-I transition temperatures higher than the corresponding eutectic mixture often exhibit nematic ranges greater than the eutectic mixture due to their ability to be supercooled. Binary mixtures from these systems and also pure 1c were used as stationary liquid phases in gas-liquid partition chromatography (glpc) to determine the selectivity of their nematic mesophases toward the positional isomers m- and p-xylene. This selectivity is an indication of the molecular order within the mesophase. The molecular order of the pure compounds was found to be in the same order as that of their N-I transition temperatures. The results from the mixtures, however, demonstrate that the N-I transition temperature is only a rough indication of order.

Additional Information

Language: English
Date: 1970
Molecular theory

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